The present invention relates generally to metallurgy, and more particularly to a method for metallurgically attaching a tube to a member.
Resistance welding (also known as electric-resistance welding) is a known metallurgical process wherein metal is heated by its own resistance to a semi-fused (i.e., soft) or fused (i.e., molten) state by the passage of very heavy electric currents for very short lengths of time and then welded by the application of pressure.
Conventional methods for metallurgically attaching together two parts also include a known method for metallurgically attaching together an inlet/outlet tube to a vehicle fuel tank cover. In the known method, a sheet-metal plate of low-carbon steel is obtained for the vehicle fuel tank cover, and a low-carbon steel tube is obtained for the inlet/outlet tube. A through hole is punched in the plate creating a full extrusion which surrounds the through hole and which projects perpendicularly away from the plate. Forming operations on the tube create a transversely-projecting annular rim on the tube. The tube is sized so that it is insertable in the through hole so as to longitudinally extend beyond both longitudinal ends of the through hole. The tube is inserted in the through hole so that the rim of the tube is seated on the plate and the full extrusion of the plate projects away from the rim. Then, the tube and the plate are brazed together near the through hole.
For the brazing operation, a furnace is required having specific temperatures and temperature gradients. The furnace must be kept with a controlled reducing atmosphere to remove the oxides from the plate and the tube before the brazing is actually performed. Also, a copper ring must be used for the filler material to perform the brazing. A ceramic chain pulley mechanism is required to move the parts through the furnace.
What is needed is a less expensive method for metallurgically attaching a tube to a member, such as metallurgically attaching an inlet/outlet tube to a vehicle fuel tank cover.
A first method of the invention is for metallurgically attaching a tube to a member. The first method includes steps a) through d). Step a) includes obtaining a member having a wall, wherein the wall includes opposing first and second sides and includes a partial extrusion extending above the first side, and wherein the partial extrusion has a through hole. Step b) includes obtaining a tube having an end portion. Step c) includes, after steps a) and b), positioning the tube and the member with the end portion contacting the second side of the wall near the partial extrusion. Step d) includes, after step c), creating a resistance welding current path through the tube and the member near the end portion and the partial extrusion and relatively moving the end portion into and deformingly against the partial extrusion creating a weld zone which includes at least some of the end portion and at least some of the partial extrusion. In one application of the first method the wall is a wall of a plate, and in a different application of the first method the wall is a wall of a tubular member.
A second method of the invention is for metallurgically attaching a tube to a member. The second method includes steps a) through d). Step a) includes obtaining a member having a wall, wherein the wall includes opposing first and second sides and includes a partial extrusion extending above the first side, wherein the partial extrusion has a through hole and a longitudinal axis aligned substantially perpendicular to the wall, and wherein the through hole is substantially coaxially aligned with the longitudinal axis. Step b) includes obtaining a tube having a tapered end portion matching the angle of the partial extrusion. Step c) includes, after steps a) and b), positioning the tube and the member with the tube aligned substantially coaxially with the longitudinal axis and with the tapered end portion contacting the second side of the wall substantially at the partial extrusion. Step d) includes, after step c), creating an annular resistance welding current path through the tube and the member at the tapered end portion and near the partial extrusion and relatively moving the tapered end portion into and deformingly against the partial extrusion creating an annular weld zone which includes at least some of the tapered end portion and at least some of the partial extrusion.
A third method of the invention is for metallurgically attaching a tube to a member. The second method includes steps a) through d). Step a) includes obtaining a member having a wall, wherein the wall includes opposing first and second sides and includes a partial extrusion extending above the first side, wherein the partial extrusion has a through hole and a longitudinal axis aligned substantially perpendicular to the wall, and wherein the through hole is substantially coaxially aligned with the longitudinal axis. Step b) includes obtaining a tube having flanged end portion. Step c) includes, after steps a) and b), positioning the tube and the member with the tube aligned substantially coaxially with the longitudinal axis and with the flanged end portion contacting the second side of the wall substantially at the partial extrusion. Step d) includes, after step c), creating an annular resistance welding current path through the tube and the member at the flanged end portion and near the partial extrusion and relatively moving the flanged end portion into and deformingly against the partial extrusion creating an annular weld zone which includes at least some of the flanged end portion and at least some of the partial extrusion.
Several benefits and advantages are derived from one or more of the methods of the invention. Resistance welding is less expensive than brazing. In the application for metallurgically attaching together a vehicle fuel tank cover and an inlet/outlet tube, instead of costing about one dollar per attachment it is expected to cost only a few cents per attachment.